Johnson happy to spearhead Australia bowling attack

In-form paceman Mitchell Johnson has welcomed the challenge of spearheading one of the most inexperienced attacks in recent history as Australia look to avoid a series whitewash in the third Test against South Africa in Sydney.

With four frontline players unavailable through injury, Johnson will partner Victorian rookie Peter Siddle, the uncapped Andrew McDonald, three-Test spinner Nathan Hauritz and either Doug Bollinger or Ben Hilfenhaus - both yet to play a Test.

Despite having just 17 Test caps, Johnson is by far the most seasoned member of the attack but insists he will thrive on the extra responsibility once the match gets under way on Saturday.

'It's going to be a challenge for me and something I'm looking forward to,' Johnson said.

'That's probably my job in the team - to try to help these young blokes through this next little period. That's something I've got to step up and do now.

'I still think we're a very strong side even though we've got a lot of young guys in the team.

'Dougie Bollinger, Andrew McDonald, Ben Hilfenhaus, they are going to come into the side with a lot of bubble.'

The Proteas are 2-0 up after comprehensive victories in Perth and Melbourne and have vowed to keep the heat on their besieged hosts in Sydney and become the first side in 122 years to complete a home series whitewash against Australia.

If they do they will officially take over as the world's number one Test nation - a prospect that does not sit easily with Johnson.

'Everyone's keeping positive; we've still got one game to go and hopefully we'll get a win and not be beaten three-nil,' he said.

'It's a pretty big deal. Australia has been the number one side for a very long side. We were outplayed this series and in India we were outplayed as well.

'Yesterday afternoon I was in a little bit of a shock coming off the field (but) I still think we're a very strong cricketing nation.

'Australian cricket over the years has deserved that number one spot. I'm still backing our team. We're going to stay positive and do our best in Sydney.'